Biological: Gottesman & Shields

To investigate the relationship between genetic make-up and schizophrenia, by looking at whether the twins of schizophrenics are also likely to develop the disorder.

Procedure

The researchers studied both identical and fraternal twins, where at least one of the twin pair had been hospitalised and diagnosed with schizophrenia. There were 62 patients in the participant sample. Zygocity was determined using fingerprint testing, blood testing, and resemblance assessments. Multiple data collection methods were used, using both primary and secondary resources, E.g. hospital notes, case histories, tape recordings, personality testing and testing to measure disordered thinking. The first twin to be admitted was called the proband. The data was analysed between each proband and their twin.

Results

Concordance rate for Mz twins = 48 %

Concordance rate for Dz twins = 17%

There was a significant difference between Mz and Dz twins in all measures